Have you ever been in mid-kiss and wondered, “Why the hell am I doing this?” If not, well firstly, I hope you have kissed someone. If you have kissed someone but haven’t asked why, then I guess you just don’t see the amusement in such a strange habit we, as humans, have picked up.

The origins of kissing have been hypothesized to stem from learned feeding behaviors of our prehistorical ancestors… Of which, have become instinctual down the generations. Gauging from the morphology of early hominid mothers teeth, they weren’t eating mash potatoes. Try rock hard tubers, and so they

“may have chewed food and passed it from their mouths into those of their toothless infants. Even after babies cut their teeth, mothers would continue to press their lips against their toddlers’ cheeks to comfort them.”

This claim is further supported by primatology. The behaviors of Bonobos, who are known for their promiscuity and affection show that,

“They do [kiss] to make up after fights, to comfort each other, to develop social bonds, and sometimes for no clear reason at all – just like us.”

But there is some data that negates the claim to instinct. See kissing is not as uniform across all cultures, as we like to think. Approximately, 10% of the human population does not kiss. That leans the hypothesis to one that supports it is a learned behavior rather than instinctual since not all humans kiss. In fact cultural anthropologists report that “Certain tribes around the world just don’t make out” and have no idea what it is all about!

Philematologists, the select few of the scientific community that specialize in the science of kissing say,

“humans do it because it helps us sniff out a quality mate. When our faces are close together, our pheromones ‘talk’ – exchanging biological information about whether or not two people will make strong offspring. Women, for example, subconsciously prefer the scent of men whose genes for certain immune system proteins are different from their own. This kind of match could yield offspring with stronger immune systems, and better chances for survival.Still, most people are satisfied with the explanation that humans kiss because it feels good. Our lips and tongues are packed with nerve endings, which help intensify all those dizzying sensations of being in love when we press our mouths to someone else’s. Experiencing such feelings doesn’t usually make us think too hard about why we kiss – instead, it drives us to find ways to do it more often.”

I think kissing is a unique phenomenon in our behavioral repertoire, don’t you? What’s your hypothesis on why we kiss?

Thanks to Scienceline’s Roberto Morabito on “Why do humans kiss?